The present invention relates to a gas etching method in which an object to be etched is etched by jetting an etching gas onto the object for etching, and a jetting nozzle used in such a gas etching method.
In order to etch an object such as a silicone wafer by using a gas, generally, the etching gas is activated by plasma or the like and, at the same time, the activated gas flow is controlled by electrodes or a magnetic force. However, in some cases, the silicone wafer, poly-silicone film and/or SiO.sub.2 film are etched by using only the etching gas.
In this case, regarding the etching method, as shown in FIG. 3, generally, an object for etching 101 mounted on a support 102 is entered into a reaction vessel 103, the reaction vessel is depressurized by evacuation through a discharge opening 104, and the etching gas is jetted on a portion to be etched of the object for etching from an end of a etching gas introducing pipe (nozzle) 105 for a predetermined time period.
The following formula (1) indicates only a typical chemical reaction of etching of silicone. The etching gas jetted from the end of etching gas introducing pipe 105 is struck against the object for etching to form reactant with the object and is gasified for effecting the etching. EQU Si+4F*.fwdarw.SiF.sub.4 .Arrow-up bold.+C.sub.2 F.sub.6 (1)
In this case, excess gas for etching is discharged from reaction vessel 103 through discharge opening 104, as shown in the arrows in FIG. 3.
As mentioned above, although the excess gas is discharged from the reaction vessel 103 through the discharge opening 104, if a path to the discharge opening 104 is long, a portion of the object 101 other than the portion to be etched is also etched away, which is problematic. In particular, when an amount to be etched is great, such as several .mu.m.about.several tens of .mu.m, no problem would be caused. However, if the amount to be etched is small, such as several hundreds of .ANG..about.several thousands of .ANG., then, a great disadvantage will be caused.